Can I change the start or end height of a line separate from each other?
The 3D-Forcer changes the height of the complete line.
For example: I managed to change my 2D lines to 3D with the Surfacedraper now I want to add to the height -1m over the complete line.
Not sure what you mean, if you want to change the height of the entire line (as your "for example" seems to imply) you can use the Offsetter to do that, keep the X and Y offsets at 0 so it'll only shift in the Z direction.
If you want to alter the z-values of individual points you could use a combination of CoordinateExtractor, VertexRemover and VertexCreator to remove specific points and put them back with new values.
I was looking for an Offsetter ! Thank you.
The Vertex transformer is to complicated for me without an example ;(
(I'm not sure if zmin and zmax of the line counts as points? )